Center position in Enter() method?

General
1

Hi,
I am new with vaadin. I have a problem with setting possition of components. I found on this forum explanation how to set center position in VerticalLayout inside Init() method. That code working fine if your application is writen inside of one.java class, but you have more pages this not working fine, because you must to write code in enter method. My general problem is: How to center elements (components) inside Enter() method?

If I run same code in Init and Enter result is different, you can see on pictures.
Init():

public class NavigatorUI extends UI {
@Override
protected void init(VaadinRequest request) {
final Panel loginPanel = new Panel("Login in Init()");

final FormLayout loginForm= new FormLayout ();
final VerticalLayout layout = new VerticalLayout();
layout.setSizeFull();
layout.setHeight("100%");

loginPanel.setContent(loginForm);

loginPanel.setWidth(null);

layout.addComponent(loginPanel);

layout.setComponentAlignment(loginPanel, Alignment.MIDDLE_CENTER);

loginPanel.setWidth("300px");

setContent(layout);

final TextField name1 = new TextField("Username:");
final TextField name2 = new TextField(" Password:");
loginForm.addComponent(name1);
loginForm.addComponent(name2);

Button button = new Button("Click Me");
button.addClickListener(new Button.ClickListener() {
public void buttonClick(ClickEvent event) { }
});
loginForm.addComponent(button);
}
}

Enter():

[code]
public class Page1 extends VerticalLayout implements View {

public Page1() {
    addComponent(new Label("Page 1"));    
}

@Override
public void enter(ViewChangeEvent event) {
            
    final Panel loginPanel = new Panel("Login in Enter()");
    
    final FormLayout loginForm= new FormLayout ();
    final VerticalLayout layout = new VerticalLayout();        
    layout.setSizeFull();    
    layout.setHeight("100%");

    loginPanel.setContent(loginForm);
        
    loginPanel.setWidth(null);
    
    layout.addComponent(loginPanel);       
    
    layout.setComponentAlignment(loginPanel, Alignment.MIDDLE_CENTER);
    
    loginPanel.setWidth("300px");
    
    addComponent(layout);
    
    final TextField name1 = new TextField("Username:");
    final TextField name2 = new TextField(" Password:");
    loginForm.addComponent(name1);
    loginForm.addComponent(name2);
    
    Button button = new Button("Click Me");
    button.addClickListener(new Button.ClickListener() {
        public void buttonClick(ClickEvent event) {
                                                    }
    });
    loginForm.addComponent(button);
}

}
[/code]

How can I center components in enter() methon? What I need to do?